JP6522125B2 - Sulfide solid electrolyte material, battery and method for producing sulfide solid electrolyte material - Google Patents

Description

  The present invention relates to a sulfide solid electrolyte material having good reduction resistance.

  With the rapid spread of information related devices such as personal computers, video cameras and mobile phones and communication devices in recent years, development of batteries used as the power source is regarded as important. Also, in the automobile industry and the like, development of high-power and high-capacity batteries for electric vehicles or hybrid vehicles is in progress. Among various batteries, lithium batteries are currently attracting attention from the viewpoint of high energy density.

  Since lithium batteries currently marketed use an electrolytic solution containing a flammable organic solvent, a safety device for suppressing temperature rise at the time of short circuit and a structure for short circuit prevention are required. On the other hand, a lithium battery in which the battery is totally solidified by changing the electrolytic solution to a solid electrolyte layer does not use a flammable organic solvent in the battery, so the safety device can be simplified, and the manufacturing cost and productivity It is considered to be excellent.

  A sulfide solid electrolyte material is known as a solid electrolyte material used for an all solid lithium battery. Patent Document 1 discloses a sulfide solid electrolyte material containing, for example, Li element, Ge element, Si element, P element and S element and having a specific peak in X-ray diffraction measurement. Moreover, it is disclosed that the reductive decomposition of sulfide solid electrolyte material can be suppressed because sulfide solid electrolyte material contains Si element.

JP, 2013-177288, A

  There is a need for a sulfide solid electrolyte material that can further suppress reductive decomposition. The present invention has been made in view of the above problems, and has as its main object to provide a sulfide solid electrolyte material having good reduction resistance.

In order to solve the above problems, in the present invention, it has a peak at the position of 2θ = 30.26 ° ± 1.00 ° in X-ray diffraction measurement using a CuKα ray, and Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} (a = 1−x + y, 0.65 ≦ x ≦ 0.75, −0.025 ≦ y ≦ 0.1, Provided is a sulfide solid electrolyte material characterized by having a composition of −0.2 ≦ z ≦ 0.

  According to the present invention, a sulfide solid electrolyte material having good reduction resistance can be obtained because the crystalline phase having the peak at around 2θ = 30.26 ° is provided, and further, it has a specific composition.

Moreover, in the present invention, it has a peak at the position of 2θ = 30.26 ° ± 1.00 ° in X-ray diffraction measurement using CuKα ray, and Li _(3.14-x) Si _{(0.34- x)} having a composition of P _{(0.70 + x)} S _(3.32-z) O _{(0.68 + z)} (−0.13 ≦ x ≦ 0.13, −0.11 ≦ z ≦ 0.11) The present invention provides a sulfide solid electrolyte material characterized by

  According to the present invention, a sulfide solid electrolyte material having good reduction resistance can be obtained because the crystalline phase having the peak at around 2θ = 30.26 ° is provided, and further, it has a specific composition.

In the present invention, the octahedron O composed of Li element and S elements, at least one element of P element and Si element, and a tetrahedron T ₁ composed of S element, P element and Si The tetrahedron T ₁ and the octahedron O share a cage, and the tetrahedron T ₂ and the octahedron O have at least one of the elements, and the tetrahedron T ₂ composed of the S element. contains a crystal structure that share vertices, the octahedron O, at least one of the tetrahedron T ₁ and the tetrahedron T ₂ are, part of the S element has been substituted with O elements, Li _{( 4-x-4y)} Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} (a = 1-x + y, 0.65? X? 0.75, -0.025? having a composition of y ≦ 0.1, −0.2 ≦ z ≦ 0) Providing a sulfide solid electrolyte material characterized.

According to the present invention, the octahedron O, the tetrahedron T ₁ and the tetrahedron T ₂ have a predetermined crystal structure (three-dimensional structure), and furthermore, the sulfide solid electrolyte material has a specific composition. A sulfide solid electrolyte material having good reducibility can be obtained.

In the present invention, the octahedron O composed of Li element and S elements, at least one element of P element and Si element, and a tetrahedron T ₁ composed of S element, P element and Si The tetrahedron T ₁ and the octahedron O share a cage, and the tetrahedron T ₂ and the octahedron O have at least one of the elements, and the tetrahedron T ₂ composed of the S element. contains a crystal structure that share vertices, the octahedron O, at least one of the tetrahedron T ₁ and the tetrahedron T ₂ are, part of the S element has been substituted with O elements, Li _{( 3.14-x)} Si _(0.34-x) P _{(0.70 + x)} S _(3.32-z) O _{(0.68 + z)} (-0.13 <= x <= 0.13, -0.11) Sulfurization characterized by having a composition of ≦ z ≦ 0.11) Solid electrolyte material.

According to the present invention, the octahedron O, the tetrahedron T ₁ and the tetrahedron T ₂ have a predetermined crystal structure (three-dimensional structure), and furthermore, the sulfide solid electrolyte material has a specific composition. A sulfide solid electrolyte material having good reducibility can be obtained.

  In the present invention, a positive electrode active material layer containing a positive electrode active material, a negative electrode active material layer containing a negative electrode active material, and an electrolyte layer formed between the positive electrode active material layer and the negative electrode active material layer. And at least one of the positive electrode active material layer, the negative electrode active material layer, and the electrolyte layer contains the above-mentioned sulfide solid electrolyte material.

  According to the present invention, a battery having high reduction resistance can be obtained by using the above-mentioned sulfide solid electrolyte material.

  Moreover, in the present invention, the method is a method for producing the above-mentioned sulfide solid electrolyte material, wherein mechanical milling is performed on a raw material composition containing the constituent components of the sulfide solid electrolyte material to obtain a precursor material. A method for producing a sulfide solid electrolyte material comprising a milling step, and a melting and quenching step to obtain the sulfide solid electrolyte material by melting and quenching the precursor material by heating, and providing the same. .

  According to the present invention, by performing the mechanical milling step and the melting and quenching step, it is possible to obtain a sulfide solid electrolyte material having good reduction resistance.

  In the said invention, it is preferable that the heating temperature in the said melt-quenching process exists in the range of 800 degreeC-1100 degreeC.

  In the present invention, an effect is obtained that a sulfide solid electrolyte material having good reduction resistance can be obtained.

It is a perspective view explaining an example of the crystal structure of the sulfide solid electrolyte material of the present invention. It is a schematic sectional drawing which shows an example of the battery of this invention. It is explanatory drawing which shows an example of the manufacturing method of the sulfide solid electrolyte material of this invention. FIG. 2 is a ternary diagram showing the composition of the sulfide solid electrolyte material obtained in Example 1; FIG. 5 is a quaternary diagram showing the composition of the sulfide solid electrolyte material obtained in Example 1; It is the result of the XRD measurement with respect to the sulfide solid electrolyte material obtained by Example 1 and Comparative Example 1. It is the result of the XRD measurement with respect to the sulfide solid electrolyte material obtained in Example 1. FIG. It is a graph which shows the relationship between the ratio of Si and P, and a lattice constant. It is a graph which shows the relationship between the ratio of S and O, and a lattice constant. It is the result of CV measurement with respect to the sulfide solid electrolyte material obtained by Example 1 and Comparative Examples 1-3. It is the result of the charging / discharging test with respect to the battery for evaluation using the sulfide solid electrolyte material obtained by Example 1 and Comparative Examples 1-3. It is the result of the charging / discharging test with respect to the battery for evaluation using the sulfide solid electrolyte material obtained by Example 1 and Comparative Examples 4-6. It is a ternary diagram explaining the sulfide solid electrolyte material obtained by Examples 2-1 to 2-3 and comparative examples 2-1 and 2-2. It is the result of the XRD measurement with respect to the sulfide solid electrolyte material obtained by Examples 2-1 to 2-3 and Comparative Examples 2-1 and 2-2. It is a ternary diagram explaining the sulfide solid electrolyte material obtained in Examples 3-1 to 3-6. It is the result of the XRD measurement with respect to the sulfide solid electrolyte material obtained in Examples 3-1 to 3-6. It is a ternary diagram explaining the sulfide solid electrolyte material obtained in Examples 4-1 and 4-2, and Comparative Examples 4-1 to 4-3. It is the result of the XRD measurement with respect to the sulfide solid electrolyte material obtained by Example 4-1, 4-2, Comparative Example 4-1 to 4-3. A battery for evaluation using the sulfide solid electrolyte material obtained in Example 2-3, Example 3-5, Example 3-6, Example 4-2, Example 5-1, and Example 5-2. Of the charge and discharge test for

  Hereinafter, the sulfide solid electrolyte material, the battery, and the method for producing the sulfide solid electrolyte material of the present invention will be described in detail.

A. Sulfide Solid Electrolyte Material First, the sulfide solid electrolyte material of the present invention will be described. The sulfide solid electrolyte material of the present invention can be roughly classified into several embodiments. Therefore, the sulfide solid electrolyte material of the present invention will be described separately in the embodiments.

1. First Embodiment The sulfide solid electrolyte material of the first embodiment has a peak at a position of 2θ = 30.26 ° ± 1.00 ° in X-ray diffraction measurement using CuKα radiation, and Li _{(3.14 −x)} Si _(0.34-x) P _{(0.70 + x)} S _(3.32-z) O _{(0.68 + z)} (−0.13 ≦ x ≦ 0.13, −0.11 ≦ z ≦ It has a composition of 0.11).

According to the first embodiment, a sulfide solid electrolyte material having a good resistance to reduction can be obtained because it has a crystal phase having a peak around 2θ = 30.26 ° and further has a specific composition. . The reason why the reduction resistance is improved is presumed to be that the introduced oxygen forms Si—O bonds in the crystal structure. The Si-O bond is electrochemically stable compared to, for example, a M-S bond (M = Ge, Si, Sn). Therefore, it is presumed that the reduction resistance of the sulfide solid electrolyte material is improved. Further, as described _later, the composition of _{Li 3.14 Si 0.34 P 0.70 S 3.32} O 0.68 is tetravalent and pentavalent cations (Si and P), anionic (S and O And the conventionally known LGPS (for example, Li _3.35 Ge _0.35 P _0.65 S ₄ , cation: anion = 4: 1) have a cation ratio of 1.04: 4. And the molar ratio of anions are different. Therefore, it is speculated that a part of Li (Li which does not contribute to ion conduction) which forms a skeletal structure in the crystal structure can be replaced by Si. It is inferred that the crystal lattice contracts with this substitution, and in response to this contraction, sulfur ions with large ion radius are replaced by oxygen ions with small ion radius. Thus, it is speculated that by adjusting the molar ratio of the cation and the anion, more oxygen can be introduced into the crystal structure, and as a result, the reduction resistance of the sulfide solid electrolyte material is improved.

  Moreover, the sulfide solid electrolyte material of the first embodiment has a wide potential window on the reduction side. Therefore, for example, when the sulfide solid electrolyte material of the first embodiment is used for a negative electrode active material layer or a solid electrolyte layer of a battery, coulombic efficiency can be improved. Further, for example, when Li is deposited on the surface of the negative electrode active material, a stable interface can be formed between the deposited Li and the sulfide solid electrolyte material. Moreover, the sulfide solid electrolyte material of the first embodiment has a crystal phase having a peak around 2θ = 30.26 °. Since this crystal phase is a crystal phase having high Li ion conductivity as described later, it can be a sulfide solid electrolyte material having good Li ion conductivity.

  Here, the sulfide solid electrolyte material described in Patent Document 1 has a crystal structure with high Li ion conductivity. The crystal phase having this crystal structure is referred to as crystal phase A '. The crystal phase A ′ is usually 2θ = 12.36 °, 14.05 °, 14.40 °, 17.38 °, 20.18 °, 20.44 °, 23.56 °, 23.96 °, It has a peak at the positions of 24.93 °, 26.96 °, 29.07 °, 29.58 °, 31.71 °, 32.66 °, 33.39 °. In these peak positions, the crystal lattice may be slightly changed depending on the material composition and the like, and may fluctuate in the range of ± 1.00 °.

  The sulfide solid electrolyte material of the first embodiment has the same crystal phase A as the crystal phase A ′. The crystalline phase A is usually 2θ = 12.66 °, 14.28 °, 14.81 °, 17.74 °, 20.64 °, 21.03 °, 23.96 °, 24.63 °, 27. It has peaks at the positions of 66 °, 29.91 ° and 30.26 °. In addition, these peak positions may also fluctuate in the range of ± 1.00 °, and preferably in the range of ± 0.50 °. The crystal phase A ′ in the sulfide solid electrolyte material described in Patent Document 1 exhibits high Li ion conductivity by conducting Li ions in the space portion of the crystal structure. Since the crystal phase A in the sulfide solid electrolyte material of the first embodiment also has the same crystal structure as the crystal phase A ′, good Li ion conductivity is exhibited. The sulfide solid electrolyte material of the first embodiment preferably has the crystal phase A as a main phase.

  Moreover, the sulfide solid electrolyte material described in Patent Document 1 may have a peak in the vicinity of 2θ = 27.33 °. Crystalline phase B 'which has this peak is a crystal phase whose Li ion conductivity is lower than crystal phase A' mentioned above. In addition, the crystal phase B 'is usually 2θ = 17.46 °, 18.12 °, 19.99 °, 22.73 °, 25.72 °, 27.33 °, 29.16 °, 29.78 It is considered to have a peak of °.

The sulfide solid electrolyte material of the first embodiment may have the same crystal phase B as the crystal phase B '. The crystal phase B is considered to be in the range of ± 1.00 ° with respect to the above-mentioned peak position of the crystal phase B ′. Although both crystal phases A and B are crystal phases exhibiting Li ion conductivity, there is a difference in the Li ion conductivity, and crystal phase B has Li ion conductivity compared to crystal phase A. It is considered low. Therefore, it is preferable to reduce the proportion of the crystal phase B. In the first embodiment, when the diffraction intensity of the peak near 2θ = 30.26 ° is I _A and the diffraction intensity of the peak near 2θ = 27.33 ° is I _B , the value of I _B / I _A For example, it is less than 0.50, preferably 0.45 or less, more preferably 0.25 or less, still more preferably 0.15 or less, and 0.07 or less Particularly preferred. Further, the value of I _B / I _A is preferably 0. In other words, it is preferable that the sulfide solid electrolyte material of the first embodiment does not have a peak around 2θ = 27.33 °.

The sulfide solid electrolyte material of the first embodiment is generally prepared by Li _(3.14-x) Si _(0.34-x) P _{(0.70 + x)} S _(3.32-z) O _{(0.68 + z).} The composition has a composition of (−0.13 ≦ x ≦ 0.13, −0.11 ≦ z ≦ 0.11). x is usually −0.13 or more, and may be −0.10 or more. On the other hand, x is usually 0.13 or less and may be 0.10 or less. z is usually −0.11 or more, and may be −0.07 or more. On the other hand, z is usually 0.11 or less and may be 0.07 or less.

The sulfide solid electrolyte material of the first embodiment is usually a sulfide solid electrolyte material having crystallinity. The sulfide solid electrolyte material of the first embodiment preferably has a high Li ion conductivity, and the Li ion conductivity of the sulfide solid electrolyte material at 25 ° C. is 1.0 × 10 ⁻⁴ S / cm or more Is preferred. Further, the shape of the sulfide solid electrolyte material of the first embodiment is not particularly limited, and may be, for example, powder. Furthermore, the average particle diameter of the powdered sulfide solid electrolyte material is preferably, for example, in the range of 0.1 μm to 50 μm.

  The sulfide solid electrolyte material of the first embodiment can be used in any application requiring Li ion conductivity. Among them, the sulfide solid electrolyte material of the first embodiment is preferably used in a battery. The method for producing the sulfide solid electrolyte material of the first embodiment will be described in detail in "C. Method for producing sulfide solid electrolyte material" described later. In addition, the sulfide solid electrolyte material of the first embodiment may have the features of each embodiment described later.

2. Second Embodiment The sulfide solid electrolyte material of the second embodiment has a peak at a position of 2θ = 30.26 ° ± 1.00 ° in X-ray diffraction measurement using a CuKα ray, and Li _{(4-x -4y)} Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} (a = 1-x + y, 0.65 <x <0.75,-0.025 <y <0 It is characterized by having a composition of 1 and -0.2 <= z <= 0).

  According to the second embodiment, a sulfide solid electrolyte material having a good resistance to reduction can be obtained because it has a crystal phase having a peak around 2θ = 30.26 ° and further has a specific composition. . In addition, since the sulfide solid electrolyte material of the second embodiment is the same as the sulfide solid electrolyte material of the first embodiment except that the composition range is different, the description here is omitted.

The sulfide solid electrolyte material of the second embodiment is generally prepared by using Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} (a = 1-x + y). , 0.65 ≦ x ≦ 0.75, −0.025 ≦ y ≦ 0.1, −0.2 ≦ z ≦ 0). The composition of Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} is derived from the following points. That is, the sulfide solid electrolyte material (sulfide solid electrolyte material having the crystal phase A) having the superionic conductor Li ₁₀ GeP ₂ S ₁₂ type structure has hitherto been Li ₄ MA ₄ -Li ₃ PA ₄ (M == Many have been reported on pseudo binary systems of Si, Sn, Ge; A = S, O). The composition on this pseudo two component can be expressed as Li _4-k M _1-k P _k A ₄ ((1-k) Li ₄ MA ₄ + k Li ₃ PA ₄ → Li _4-k M _1-k P _k A ₄ ). On the other hand, in the Li ₂ S-SiO ₂ -P ₂ S ₅ pseudo ternary system, the composition corresponding to Li ₄ MA ₄ -Li ₃ PA ₄ is Li ₄ SiS ₂ O ₂ -Li ₃ PS ₄ and the pseudo two-component The system can be expressed as Li _4-x Si _1-x P _x S _{2 + 2x} O _2-2x . In the Li ₂ S-SiO ₂ -P ₂ S ₅ quasi ternary system, the superionic conductor Li ₁₀ GeP ₂ S ₁₂ type even with a composition slightly deviated from the Li ₄ SiS ₂ O ₂ -Li ₃ PS ₄ pseudo binary system A sulfide solid electrolyte material having a structure is obtained. Therefore, when the deviation from Li ₄ SiS ₂ O ₂ -Li ₃ PS ₄ pseudo two-component wire connection is shown using a parameter y representing composition substitution of 4Li ⁺ ⇔Si ^{4 +} , Li _4-x-4y Si _{1- x + y P x S 2 +} 2x-2y O 2-2x + 2y and can be represented. Furthermore, it can be expressed as Li _{4-x-4 y} Si _{1-x + y} P _x S _{2 + 2 x-2 y-z} O _{2-2 x + 2 y + z} using a parameter z representing the ratio of S ² -⇔O ^2- . When synthesizing with a composition of z ≠ 0, it is preferable to use P ₂ O ₅ or SiS ₂ in addition to the raw materials Li ₂ S, SiO ₂ and P ₂ S ₅ . Here, in order to make it easy to see the composition formula, _assuming that a = 1−x + y, Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} The composition formula is obtained.

  In the above composition formula, x is usually 0.65 or more, and may be 0.67 or more. On the other hand, x is usually 0.75 or less, and may be 0.73 or less. y is usually −0.025 or more, and may be −0.03 or more. On the other hand, y is usually 0.1 or less and may be 0.08 or less. z is usually −0.2 or more, and may be −0.15 or more. On the other hand, z is usually 0 or less, and may be 0.8 or less.

3. Third Embodiment FIG. 1 is a perspective view illustrating an example of the crystal structure of a sulfide solid electrolyte material according to a third embodiment. In the crystal structure shown in FIG. 1, octahedron O has Li as a central element, and has six S (note that part of S may be substituted with O) at the apex of the octahedron. ing. Octahedron O is, for example, LiS _6-x O _x (0 ≦ x <6) octahedron. Tetrahedron T ₁ has at least one of Si and P as a central element, and has 4 S (note that part of S may be substituted with O) at the apex of the tetrahedron . The tetrahedron T ₁ is, for example, both a SiS _4-x O _x (0 ≦ x <4) tetrahedron and a PS _4-x O _x (0 ≦ x <4) tetrahedron. Tetrahedron T ₂ has at least one of Si and P as a central element, and has four S (wherein a part of S may be substituted with O) at the apex of the tetrahedron . The tetrahedron T ₂ is, for example, PS _4-x O _x (0 ≦ x <4) tetrahedron.

Also, the sulfide solid electrolyte material of the third embodiment, octahedron O, at least one of the tetrahedron T ₁ and tetrahedron T ₂ is one in which part of the S element is replaced with O elements. In addition, it can be confirmed by analysis of the XRD pattern by the Rietveld method, neutron diffraction, etc. that a part of S element is substituted by O element, for example. In addition, tetrahedron T ₁ and octahedron O share 、, tetrahedron T ₂ and octahedron O share apex. The sulfide solid electrolyte material of the third embodiment has the same composition as that of the first embodiment described above.

According to the third embodiment, the octahedron O, the tetrahedron T ₁ and the tetrahedron T ₂ have a predetermined crystal structure (three-dimensional structure), and further, the sulfide solid electrolyte material has a specific composition. The sulfide solid electrolyte material can have good reduction resistance.

  The sulfide solid electrolyte material of the third embodiment is not particularly limited as long as it has the above-mentioned crystal structure. Moreover, it is preferable that the sulfide solid electrolyte material of a 3rd embodiment mainly contains the said crystal structure. The phrase “containing mainly the above crystal structure” means that the ratio of the above crystal structure is the largest with respect to all the crystal phases contained in the sulfide solid electrolyte material. The proportion of the crystal structure is, for example, 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more. In addition, the ratio of the said crystal structure can be measured by synchrotron radiation XRD, for example. In particular, the sulfide solid electrolyte material of the third embodiment is preferably a single phase material of the above crystal structure. In addition, the sulfide solid electrolyte material of the third embodiment may have the characteristics of the first embodiment or the second embodiment described above.

4. Fourth Embodiment The sulfide solid electrolyte material of the fourth embodiment has a specific crystal structure, and further, Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _{(4-2a- z)} O _{(2a + z)} (a = 1-x + y, 0.65 <x <0.75,-0.025 <y <0.1,-0.2 <z <0) I assume.

According to the fourth embodiment, the octahedron O, the tetrahedron T ₁ and the tetrahedron T ₂ have a predetermined crystal structure (three-dimensional structure), and further, the sulfide solid electrolyte material has a specific composition. The sulfide solid electrolyte material can have good reduction resistance. In addition, since the sulfide solid electrolyte material of the fourth embodiment is the same as the sulfide solid electrolyte material of the third embodiment except that the composition range is different, the description here is omitted.

B. Battery FIG. 2 is a schematic cross-sectional view showing an example of the battery of the present invention. Battery 10 in FIG. 2 is formed between positive electrode active material layer 1 containing a positive electrode active material, negative electrode active material layer 2 containing a negative electrode active material, and positive electrode active material layer 1 and negative electrode active material layer 2. An electrolyte layer 3, a positive electrode current collector 4 for collecting current of the positive electrode active material layer 1, a negative electrode current collector 5 for collecting current of the negative electrode active material layer 2, and a battery case 6 for housing these members It is possessed. In the present invention, at least one of the positive electrode active material layer 1, the negative electrode active material layer 2, and the electrolyte layer 3 contains the sulfide solid electrolyte material described in the above "A. sulfide solid electrolyte material". I assume.

According to the present invention, a battery having high reduction resistance can be obtained by using the above-mentioned sulfide solid electrolyte material.
Hereinafter, the battery of the present invention will be described for each configuration.

1. Negative Electrode Active Material Layer The negative electrode active material layer in the present invention is a layer containing at least a negative electrode active material, and may contain at least one of a solid electrolyte material, a conductive material, and a binder as needed. good.

  As a negative electrode active material, a metal active material and a carbon active material can be mentioned, for example. As a metal active material, Li, In, Al, Si, Sn, etc. can be mentioned, for example. The metal active material may be a single metal such as Li or an alloy such as a Li alloy. On the other hand, examples of the carbon active material include mesocarbon microbeads (MCMB), highly oriented graphite (HOPG), hard carbon, soft carbon and the like.

  In the present invention, preferably, the negative electrode active material layer contains a solid electrolyte material, and the solid electrolyte material is the above-mentioned sulfide solid electrolyte material. It is because the sulfide solid electrolyte material mentioned above has high reduction resistance. The proportion of the above-mentioned sulfide solid electrolyte material contained in the negative electrode active material layer varies depending on the type of battery, but it is, for example, in the range of 0.1% by volume to 80% by volume, in particular 1% by volume to 60% by volume It is preferable to be in the range, particularly in the range of 10% by volume to 50% by volume.

  The negative electrode active material layer may further contain a conductive material. The conductivity of the negative electrode active material layer can be improved by the addition of the conductive material. Examples of the conductive material include acetylene black, ketjen black, carbon fiber and the like. In addition, the negative electrode active material layer may contain a binder. As a kind of binder, fluorine-containing binders, such as polyvinylidene fluoride (PVDF), etc. can be mentioned, for example. Moreover, it is preferable that the thickness of a negative electrode active material layer exists in the range of 0.1 micrometer-1000 micrometers, for example.

2. Electrolyte Layer The electrolyte layer in the present invention is a layer formed between the positive electrode active material layer and the negative electrode active material layer. The electrolyte layer is not particularly limited as long as it is a layer capable of conducting ions, but is preferably a solid electrolyte layer composed of a solid electrolyte material. This is because a battery with higher safety can be obtained as compared to a battery using an electrolytic solution. Furthermore, in the present invention, the solid electrolyte layer preferably contains the above-mentioned sulfide solid electrolyte material. The proportion of the sulfide solid electrolyte material contained in the solid electrolyte layer is, for example, preferably in the range of 10% by volume to 100% by volume, and more preferably in the range of 50% by volume to 100% by volume. The thickness of the solid electrolyte layer is, for example, preferably in the range of 0.1 μm to 1000 μm, and more preferably in the range of 0.1 μm to 300 μm. Moreover, as a method of forming a solid electrolyte layer, for example, a method of compression molding a solid electrolyte material can be mentioned. The electrolyte layer in the present invention may be a layer composed of an electrolytic solution.

3. Positive Electrode Active Material Layer The positive electrode active material layer in the present invention is a layer containing at least a positive electrode active material, and may contain at least one of a solid electrolyte material, a conductive material, and a binder as needed. good. In particular, in the present invention, it is preferable that the positive electrode active material layer contains a solid electrolyte material, and the solid electrolyte material be the above-mentioned sulfide solid electrolyte material. The proportion of the above-mentioned sulfide solid electrolyte material contained in the positive electrode active material layer varies depending on the type of battery, but it is, for example, in the range of 0.1% by volume to 80% by volume, in particular 1% by volume to 60% by volume It is preferable to be in the range, in particular in the range of 10% by volume to 50% by volume. Moreover, as a positive electrode active material, for example, LiCoO ₂ , LiMnO ₂ , Li ₂ NiMn ₃ O ₈ , LiVO ₂ , LiCrO ₂ , LiFePO ₄ , LiCoPO ₄ , LiNiO ₂ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ mag can be mentioned. The conductive material and the binder used in the positive electrode active material layer are the same as those in the above-described negative electrode active material layer. Moreover, it is preferable that the thickness of a positive electrode active material layer exists in the range of 0.1 micrometer-1000 micrometers, for example.

4. Other Configurations The battery of the present invention at least includes the negative electrode active material layer, the electrolyte layer, and the positive electrode active material layer described above. Furthermore, usually, it has a positive electrode current collector for collecting current in the positive electrode active material layer, and a negative electrode current collector for collecting current in the negative electrode active material layer. Examples of the material of the positive electrode current collector include SUS, aluminum, nickel, iron, titanium and carbon. On the other hand, as a material of the negative electrode current collector, for example, SUS, copper, nickel, carbon and the like can be mentioned. The thickness, shape, and the like of the positive electrode current collector and the negative electrode current collector are preferably selected appropriately in accordance with the application of the battery and the like. Moreover, the battery case of a general battery can be used for the battery case used for this invention. As a battery case, a battery case made of SUS etc. can be mentioned, for example.

5. Battery The battery of the present invention may be a primary battery or a secondary battery, but among them, a secondary battery is preferable. This is because the battery can be repeatedly charged and discharged, and it is useful as, for example, an on-vehicle battery. Examples of the shape of the battery of the present invention include coin, laminate, cylindrical and square. Further, the method for producing the battery of the present invention is not particularly limited as long as the method can obtain the above-mentioned battery, and the same method as a general method for producing a battery can be used. For example, in the case where the battery of the present invention is an all solid battery, as an example of the manufacturing method, the material constituting the positive electrode active material layer, the material constituting the solid electrolyte layer, and the material constituting the negative electrode active material layer are sequentially By pressing, a power generation element is produced, this power generation element is stored in the inside of a battery case, and the method etc. of caulking a battery case can be mentioned.

C. Method of Producing Sulfide Solid Electrolyte Material FIG. 3 is an explanatory view showing an example of a method of producing a sulfide solid electrolyte material of the present invention. In the method for producing a sulfide solid electrolyte material in FIG. 3, first, Li ₂ S, P ₂ S ₅ , and SiO ₂ are mixed to produce a raw material composition. At this time, in order to prevent deterioration of the raw material composition due to moisture in the air, it is preferable to prepare the raw material composition under an inert gas atmosphere. Next, mechanical milling is performed on the raw material composition to obtain a precursor material. The precursor material is then melted by heating and then quenched. Thereby, a sulfide solid electrolyte material is obtained.

According to the present invention, by performing the mechanical milling step and the melting and quenching step, it is possible to obtain a sulfide solid electrolyte material having good reduction resistance.
Hereinafter, the method for producing the sulfide solid electrolyte material of the present invention will be described step by step.

1. Mechanical Milling Step The mechanical milling step in the present invention is a step of subjecting the raw material composition containing the component of the sulfide solid electrolyte material to mechanical milling to obtain a precursor material. The raw material composition is crushed by mechanical milling to improve uniformity.

The raw material composition in the present invention contains Li element, Si element, P element, S element and O element. The compound containing Li element can mention the sulfide of Li, for example. Specifically as Li sulfide, Li ₂ S can be mentioned. Moreover, as a compound containing Si element, the sulfide of Si etc. can be mentioned, for example. Specific examples of sulfides of Si include SiS _{2 and the} like. Moreover, the compound containing P element can mention the simple substance of P, the sulfide of P, etc., for example. Specific examples of the sulfide of P include P ₂ S _{5 and the} like. The compound containing the S element is not particularly limited, and may be a single substance or a sulfide. As a sulfide, the sulfide containing the element mentioned above can be mentioned. The compound containing an O element is, for example, an oxide, and an oxide of Li, Si or P can be mentioned. Specifically, SiO _{2 and the} like can be mentioned.

  Mechanical milling is a method of grinding a sample while applying mechanical energy. Examples of mechanical milling include vibration mills, ball mills, turbo mills, mechanofusions, disk mills and the like, among which vibration mills are preferred.

  The conditions of the vibration mill are not particularly limited as long as the desired precursor material can be obtained. The vibration amplitude of the vibration mill is, for example, preferably in the range of 5 mm to 15 mm, and more preferably in the range of 6 mm to 10 mm. The vibration frequency of the vibration mill is, for example, preferably in the range of 500 rpm to 2000 rpm, and more preferably in the range of 1000 rpm to 1800 rpm. The filling rate of the sample of the vibration mill is, for example, preferably in the range of 1% by volume to 80% by volume, more preferably in the range of 5% by volume to 60% by volume, and particularly in the range of 10% by volume to 50% by volume. The processing time of the vibration mill is not particularly limited. Moreover, in the vibration mill, it is preferable to use a vibrator (for example, a vibrator made of alumina).

2. Melt-quenching step The melt-quenching step in the present invention is a step of melting the precursor material by heating and quenching to obtain the sulfide solid electrolyte material.

  In the present invention, at least a portion of the precursor material is melted by heating. The heating temperature is, for example, 550 ° C. or higher, preferably 700 ° C. or higher, and more preferably 800 ° C. or higher. If the heating temperature is too low, the precursor material may not be sufficiently melted (melted). On the other hand, the heating temperature is, for example, 1800 ° C. or less, preferably 1500 ° C. or less, and more preferably 1100 ° C. or less. If the heating temperature is too high, the precursor material may react excessively with the reaction vessel (eg quartz tube).

  The heating time is preferably adjusted to obtain a desired sulfide solid electrolyte material, for example, in the range of 30 minutes to 10 hours, and preferably in the range of 1 hour to 5 hours. Further, heating of the precursor material is preferably performed in an inert gas atmosphere or in vacuum from the viewpoint of preventing oxidation.

  In the present invention, the precursor material in the molten state is quenched. The quenching method is usually a method of bringing a refrigerant into contact with the precursor material in a molten state. "Contact" refers to the case where the refrigerant directly contacts the precursor material in the molten state, and the case where the refrigerant indirectly contacts the precursor material in the molten state via the reaction vessel or the like. The temperature of the refrigerant is not particularly limited, but may be, for example, 30 ° C. or less, may be 15 ° C. or less, or 0 ° C. or less. The refrigerant may be liquid, solid or gas. As a refrigerant | coolant, water, ice, a metal, the atmosphere etc. can be mentioned specifically ,. As the quenching method, for example, a water cooling method, an air cooling method, a single roll method and the like can be mentioned.

The cooling rate in the quenching is, for example, preferably 1 K / sec or more, more preferably 10 K / sec or more, and still more preferably 10 ² K / sec or more. Further, the quenching in the present invention is preferably a treatment of cooling the temperature of the sulfide solid electrolyte material to 100 ° C. or less, and more preferably a treatment of cooling to 50 ° C. or less. Further, the sulfide solid electrolyte material obtained by the present invention is the same as the contents described in the above "A. sulfide solid electrolyte material", and thus the description thereof is omitted here.

  The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and it has substantially the same configuration as the technical idea described in the claims of the present invention, and any one having the same function and effect can be used. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be more specifically described by way of examples.

Example 1
Lithium sulfide (Li ₂ S), diphosphorus pentasulfide (P ₂ S ₅ ) and silicon dioxide (SiO ₂ ) were used as starting materials. These powders were mixed in a glove box under an argon atmosphere at a ratio of 1.2703 g of Li ₂ S, 1.3699 g of P ₂ S ₅ and 0.3597 g of SiO ₂ to obtain a raw material composition. Next, the obtained raw material composition was milled for 90 minutes using a vibration mill (manufactured by CMT).

The obtained precursor material was placed in a carbon-coated quartz tube (carbon crucible) and vacuum-sealed. The pressure of the vacuum sealed quartz tube was about 30 Pa. Next, the quartz tube was placed in a baking furnace, heated from room temperature to 1000 ° C. over 2.5 hours, maintained at 1000 ° C. for 5 hours, and then quenched by pouring into cold water. This _gave a sulfide solid electrolyte material having a composition of _{Li 3.14 Si 0.34 P 0.70 S 3.32} O 0.68. In addition, the composition of Example 1 is x = 0.70, y = 0 in Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} . It corresponds to the composition of 04 and z = 0.

Further, the composition of Example 1 can be expressed as shown in FIG. 4 by a ternary diagram of Li ₂ S, P ₂ S ₅ and SiO ₂ which are starting materials. _Also, if you define _{A = S 3.32 / 4 O 0.68} / 4, the composition of Example _1, does not correspond to the composition of the tie line of Li 4 SiA ₄ and _Li 3 PA _4. Here, as shown in FIG. 5, a ternary diagram in the case where the anion component is only O element is shown on the upper side of FIG. 5, and a ternary diagram in the case where the anion component is only S element is shown on the lower side The composition of Example 1 in which the anion component is an O element and an S element can be shown between the two. Further, in FIG. 5, Li ₄ SiO ₄ , Li ₄ SiA ₄ and Li ₄ SiS ₄ correspond to so-called ortho compositions of the Si system, and Li ₃ PO ₄ , Li ₃ PA ₄ and Li ₃ PS ₄ are so-called P It corresponds to the ortho composition of the system. The composition of Example 1 is a novel composition which does not correspond to the composition on the tie line of Li ₄ SiA ₄ and Li ₃ PA ₄ .

Comparative Examples 1 to 3
The sulfide solid electrolyte material of Comparative Examples 1 to 3 was obtained using the same method as that described in Example 1 of Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-177288). The composition of Comparative Example 1 is Li _3.35 Ge _0.35 P _0.65 S ₄ and the composition of Comparative Example 2 is Li _3.27 Sn _0.27 P _0.73 S ₄ ; The composition was Li _3.55 Si _0.45 P _0.55 S ₄ . The composition of Comparative Example 3 corresponds to the composition on the tie line of Li ₄ SiS ₄ and Li ₃ PS ₄ in FIG. Although not shown, the composition of Comparative Example 1 corresponds to the composition on the tie line of Li ₄ GeS ₄ and Li ₃ PS ₄ , and the composition of Comparative Example 2 is on the tie line of Li ₄ SnS ₄ and Li ₃ PS ₄ It corresponds to the composition of

[Comparative Examples 4 to 6]
The sulfide solid electrolyte materials of Comparative Examples 4 to 6 were obtained using the same method as that described in Example 1 of Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-177288). The composition of Comparative Example 4 is _{Li 10.35 Si 1.35 P 1.65 S 12} (Li 3.45 Si 0.45 P 0.55 S 4), the composition of Comparative Example 5 _Li 10 _GeP 2 S ₁₂ (Li _3.33 Ge _0.33 P _0.67 S ₃ ), and the composition of Comparative Example 6 is Li _9.81 Sn _0.81 P _2.19 S ₁₂ (Li _3.27 Sn _0.27 P) It was _0.73 S ₄ ).

[Evaluation]
[X-ray diffraction measurement]
X-ray diffraction (XRD) measurement was performed on the sulfide solid electrolyte material obtained in Example 1 and Comparative Example 1. The XRD measurement was performed on the powder sample under the condition of using CuKα ray under an inert atmosphere. The results are shown in FIG. As shown in FIG. 6, in Example 1, 2θ = 12.66 °, 14.28 °, 14.81 °, 17.74 °, 20.64 °, 21.03 °, 23.96 °, 24. The peaks appeared at positions of 63 °, 27.66 °, 29.91 ° and 30.26 °. These peaks are peaks of crystalline phase A having high Li ion conductivity. In addition, in Example 1, the crystal phase A was obtained as a substantially single phase, and the peak of the crystal phase B having low Li ion conductivity was not confirmed. On the other hand, in Comparative Example 1, a peak of the crystal phase A ′ substantially matching the crystal phase A was obtained. Specifically, 2θ = 12.36 °, 14.05 °, 14.40 °, 17.38 °, 20.18 °, 20.44 °, 23.56 °, 23.96 °, 24.93 It has a peak in the position of °, 26.96 °, 29.07 °, 29.58 °, 31.71 °, 32.66 °, 33.39 °.

  Moreover, FIG. 7 is the result of the XRD measurement with respect to the sulfide solid electrolyte material obtained in Example 1. FIG. As shown in the left side of FIG. 7, it was confirmed that the sulfide solid electrolyte material obtained in Example 1 can be synthesized with good reproducibility even if the experiment is performed a plurality of times. On the other hand, as shown on the right side of FIG. 7, when the peak position near 2θ = 30 ° was confirmed in detail, it was confirmed that the lattice constant a changed from 8.32487 (Å) to 8.422 (Å) (Change of 0.09713 (Å)).

Here, it is assumed that the change of the lattice constant a occurs with the change of the ratio of Si and P. When the ratio of Si and P is Si: P = 1−k: k, the change of 0.09713 (Å) is the result of the previous research (Hori, S., Suzuki, K., Hirayama, M., Kato) , Y., Saito, T., Yonemura, M. & Kanno, R. (2014). Based on Faraday Discusss. 176, 83-94.), K changes by 0.25 as shown in FIG. Equivalent to This change is obtained as follows: −0.13 ≦ x ≦ 0. In Li _(3.14-x) Si _(0.34-x) P _{(0.70 + x)} S _(3.32-z) O _{(0.68 + z)} . It corresponds to 13.

On the other hand, it is assumed that a change in lattice constant a occurs with a change in the ratio of S and O. When the ratio of S and O is S: O = 4-z: z, the change of 0.09713 (Å) is the result of the previous research (Takada, K., Osada, M., Ohta, N., Inada) Solid State Ionics 176, 2355-2359. And Satoshi Hori, Kota Suzuki, Masaaki Hirayama, T., Kajiyama, A., Sasaki, H., Kondo, S., Watanabe, M. & Sasaki, T. (2005). As shown in Fig. 9 (a), this corresponds to a change of 0.225 in z, as shown in Fig. 9 (a), based on the Japan Powder and Powder Metallurgy Association 2015 Spring Conference (Tokyo) 2-39A. This change is obtained as follows: −0.11 ≦ z ≦ 0. In Li _(3.14-x) Si _(0.34-x) P _{(0.70 + x)} S _(3.32-z) O _{(0.68 + z)} It corresponds to 11. As shown in FIG. 9B, the lattice constant a of Li ₃ PS ₃ O is 8.17201 (Å), and the lattice constant a of Li ₃ PS _3.2 O _0.8 is 8.26226 ( Å). From the results of Example 1 and these considerations, Li _(3.14-x) Si _(0.34-x) P _{(0.70 + x)} S _{(3.3 2-z)} O _{(0.68 + z)} (-0 ₎ It was confirmed that the desired effect was obtained when .13 x x 0.1 0.13 and -0.11 z z 0.1 0.11).

[Cyclic voltammetry measurement]
Cyclic voltammetry (CV) measurement was performed using the sulfide solid electrolyte material obtained in Example 1 and Comparative Examples 1 to 3. Specifically, a sample (thickness 1 mm) in which SUS, a sulfide solid electrolyte material, and Li were laminated was prepared and measured at a sweep rate of 1 mV / sec. The results are shown in FIG. As shown in FIG. 10, in Comparative Example 1 (Ge-based) and Comparative Example 2 (Sn-based), a peak around +0 V (a peak corresponding to the dissolution of Li) is hardly confirmed. In addition, the current in the reduction direction near -0 V is considered not to correspond to Li precipitation but to decomposition of the sulfide solid electrolyte material.

  On the other hand, in Comparative Example 3 (Si-based) and Example 1 (Si-O-based), a peak for Li dissolution was clearly confirmed around + 0V. In addition, in Comparative Example 3 (Si-based), the current value corresponding to Li deposition near -0 V decreased as the cycle progressed. It is considered that this is because a reductive decomposition reaction of the sulfide solid electrolyte material occurs at the interface of the sulfide solid electrolyte material and Li, and a resistance layer is formed as the cycle progresses. On the other hand, in Example 1 (Si-O system), the reduction rate of the current value corresponding to Li deposition near -0 V was small even if the cycle progressed. Therefore, it was suggested that a stable interface was formed between the sulfide solid electrolyte material and Li.

[Charge and discharge test]
An evaluation battery was produced using the sulfide solid electrolyte material obtained in Example 1 and Comparative Examples 1 to 3. For the positive electrode active material layer, a mixture of LiCoO ₂ and the sulfide solid electrolyte material obtained in Comparative Example 1 is used, and for the solid electrolyte layer, the sulfide solid electrolyte material obtained in Comparative Examples 1 to 3 is used. The Li foil was used for the negative electrode active material layer. The charge / discharge test was performed between 2.5 V and 4.2 V at a constant current of 0.0636 mA / cm ² . The results of the initial discharge capacity and the coulombic efficiency are shown in FIG.

  As shown in FIG. 11, in Example 1, the initial discharge capacity was 90 mAh / g, the coulombic efficiency was 87%, and both values were higher than Comparative Examples 1 to 3. In Comparative Examples 1 to 3, the molar ratio of the tetravalent and pentavalent cation to the anion is 1: 4, but in Example 1, the tetravalent and pentavalent cation (Si and P) and the anion ( The molar ratio to S and O) is 1.04: 4. It was suggested that the difference in the molar ratio of the cation and the anion may also contribute to the improvement of the initial discharge capacity and the coulombic efficiency.

Moreover, the battery for evaluation was produced using the sulfide solid electrolyte material obtained by Example 1 and Comparative Examples 4-6. For the positive electrode active material layer, a mixture of LiCoO ₂ coated on the surface with LiNbO ₃ and the sulfide solid electrolyte material obtained in Comparative Example 5 is used, and for the solid electrolyte layer, Example 1 and Comparative Example 4 Li foil was used for the negative electrode active material layer using the sulfide solid electrolyte material obtained by -6. The charge / discharge test was performed between 2.55 V and 4.25 V at a constant current of 0.015 mA / cm ^{2 to} 0.019 mA / cm ² . The current values were standardized so that the C rate was equivalent to 1/20 C for each evaluation battery. The results are shown in FIG. As shown to Fig.12 (a), Example 1 was able to obtain a favorable capacity | capacitance compared with Comparative Examples 4-6. Further, as shown in FIGS. 12 (b) and 12 (c), in Example 1, the capacity retention rate (FIG. 12 (b)) and the cycle efficiency (FIG. 12 (c)) both have values close to 100%. Indicated.

[Examples 2-1 to 2-3, Comparative Examples 7-1 and 7-2]
A sulfide solid electrolyte material was obtained in the same manner as in Example 1, except that the ratio of the raw materials contained in the raw material composition was changed so as to obtain the composition shown in Table 1. These compositions correspond to compositions in the case of fixing x = 0 and z = 0 and making x variable in the ternary system shown in FIG. X-ray diffraction (XRD) measurement was performed on the obtained sulfide solid electrolyte material. The measuring method is the same as described above. The results are shown in FIG. As shown in FIG. 14, in Examples 2-1 to 2-3 (x = 0.65, 0.7, 0.75), as in Example 1, the crystal phase A with high Li ion conductivity is It was obtained almost in single phase. On the other hand, in Comparative Examples 7-1 and 7-2 (x = 0.8, 0.9), the crystalline phase A was not obtained at least as the main phase. From these results, it was confirmed that crystalline phase A was obtained in the range of 0.65 ≦ x ≦ 0.75.

[Examples 3-1 to 3-6]
A sulfide solid electrolyte material was obtained in the same manner as in Example 1, except that the ratio of the raw materials contained in the raw material composition was changed so as to obtain the composition shown in Table 1. These compositions correspond to compositions in the case where x = 0.7 and z = 0 are fixed and y is variable in the ternary system shown in FIG. Example 3-3 has the same composition as Example 1. X-ray diffraction (XRD) measurement was performed on the obtained sulfide solid electrolyte material. The measuring method is the same as described above. The results are shown in FIG. As shown in FIG. 16, in Examples 3-1 to 3-6 (y = −0.025 to 0.1), as in Example 1, the crystal phase A having high Li ion conductivity is almost single phase. It was obtained in From these results, it was confirmed that the crystal phase A was obtained in the range of −0.025 ≦ y ≦ 0.1.

[Examples 4-1 and 4-2, Comparative Examples 8-1 to 8-3]
A sulfide solid electrolyte material was obtained in the same manner as in Example 1, except that the ratio of the raw materials contained in the raw material composition was changed so as to obtain the composition shown in Table 1. These compositions correspond to the compositions when x = 0.7 and y = 0 are fixed and z is variable (variable in a direction not shown) in the ternary system shown in FIG. X-ray diffraction (XRD) measurement was performed on the obtained sulfide solid electrolyte material. The measuring method is the same as described above. The results are shown in FIG. As shown in FIG. 18, in Examples 4-1 and 4-2 (z = −0.2 to 0), as in Example 1, a crystal phase A having high Li ion conductivity is obtained in a substantially single phase. It was done. On the other hand, in Comparative Examples 8-1 to 8-3 (x = 0.4, 0.2, -0.4), the crystalline phase A was not obtained at least as the main phase. From these results, it was confirmed that the crystalline phase A was obtained in the range of −0.2 ≦ z ≦ 0.

[Examples 5-1, 5-2]
A sulfide solid electrolyte material was obtained in the same manner as in Example 1, except that the ratio of the raw materials contained in the raw material composition was changed so as to obtain the composition shown in Table 1. The composition of Example 5-1 is x = 0.65, y = 0 in Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} . It corresponds to the composition of 025 and z = 0. The composition of Example 5-2 is such that x = 0.75, y = 0 in Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} . It corresponds to the composition of 025 and z = 0.

  As shown in FIG. 14, FIG. 16, and FIG. 18, in each example, similar XRD patterns were obtained, and similar lattice constants were obtained. Therefore, it was confirmed that these sulfide solid electrolyte materials have the crystal phase A having high Li ion conductivity, and contain the Si element and the O element in the crystal structure. On the other hand, in each of the examples, similar XRD patterns were obtained despite the difference in composition. The reason is that both (A) the ratio of Si / P in the crystal structure or the possibility that solid solutions having different ratios of S / O may be obtained, and (B) the possibility that trace impurities are formed. Or either one is considered. From the viewpoint of solid chemistry, it is considered that (A) and (B) do not impair the reduction resistance as long as the degree of change of the composition and the XRD pattern is as shown in each example.

In fact, using some of the sulfide solid electrolyte materials obtained in the examples as a solid electrolyte layer, a battery for evaluation was produced. Specifically, LiCoO ₂ was used for the positive electrode active material layer, the sulfide solid electrolyte material obtained in the example was used for the solid electrolyte layer, and Li foil was used for the negative electrode active material layer. The results are shown in FIG. As shown in FIG. 19, good reduction resistance was shown in any of the examples. Thus, it was confirmed that (A) and (B) did not impair the reduction resistance.

1 ... positive electrode active material layer 2 ... negative electrode active material layer 3 ... electrolyte layer 4 ... positive electrode current collector 5 ... negative electrode current collector 6 ... battery case 10 ... battery

Claims (7)

It has a peak at the position of 2θ = 30.26 ° ± 1.00 ° in X-ray diffraction measurement using CuKα ray,
Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} (a = 1-x + y, 0.65? X? 0.75, -0.. A sulfide solid electrolyte material characterized by having a composition of 025 ≦ y ≦ 0.1 and −0.2 ≦ z ≦ 0). It has a peak at the position of 2θ = 30.26 ° ± 1.00 ° in X-ray diffraction measurement using CuKα ray,
Li _(3.14-x) Si _(0.34-x) P _{(0.70 + x)} S _(3.32-z) O _{(0.68 + z)} (-0.13 <= x <= 0.13, -0 Sulfide solid electrolyte material characterized by having a composition of 11 ≦ z ≦ 0.11). And octahedron O composed of Li element and S elements, at least one element of P element and Si element, and a tetrahedron T ₁ composed of S elements, at least one element of P element and Si element, And a tetrahedron T ₂ composed of S element, wherein the tetrahedron T ₁ and the octahedron O share a weir, and the tetrahedron T ₂ and the octahedron O share a vertex. Contains
In at least one of the octahedron O, the tetrahedron T ₁ and the tetrahedron T ₂ , a part of the S element is substituted with an O element,
Li _(4-x-4y) Si _{(1-x + y)} P _(x) S _(4-2a-z) O _{(2a + z)} (a = 1-x + y, 0.65? X? 0.75, -0.. A sulfide solid electrolyte material characterized by having a composition of 025 ≦ y ≦ 0.1 and −0.2 ≦ z ≦ 0). And octahedron O composed of Li element and S elements, at least one element of P element and Si element, and a tetrahedron T ₁ composed of S elements, at least one element of P element and Si element, And a tetrahedron T ₂ composed of S element, wherein the tetrahedron T ₁ and the octahedron O share a weir, and the tetrahedron T ₂ and the octahedron O share a vertex. Contains
In at least one of the octahedron O, the tetrahedron T ₁ and the tetrahedron T ₂ , a part of the S element is substituted with an O element,
Li _(3.14-x) Si _(0.34-x) P _{(0.70 + x)} S _(3.32-z) O _{(0.68 + z)} (-0.13 <= x <= 0.13, -0 Sulfide solid electrolyte material characterized by having a composition of 11 ≦ z ≦ 0.11). A battery comprising a positive electrode active material layer containing a positive electrode active material, a negative electrode active material layer containing a negative electrode active material, and an electrolyte layer formed between the positive electrode active material layer and the negative electrode active material layer. ,
At least one of the positive electrode active material layer, the negative electrode active material layer, and the electrolyte layer contains the sulfide solid electrolyte material according to any one of claims 1 to 4. battery. A method for producing a sulfide solid electrolyte material according to any one of claims 1 to 4, wherein
Mechanical milling of the raw material composition containing the constituents of the sulfide solid electrolyte material to obtain a precursor material;
A melting and quenching step of obtaining the sulfide solid electrolyte material by melting and rapidly cooling the precursor material;
A method for producing a sulfide solid electrolyte material, comprising:   The heating temperature in the said melt-quenching process exists in the range of 800 degreeC-1100 degreeC, The manufacturing method of the sulfide solid electrolyte material of Claim 6 characterized by the above-mentioned.

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